The present invention relates to one direction valves, for example, for containers. More particularly, the invention relates to one direction valves, and containers including such valves, for ventilation, and short term partial vacuum or pressure retention of or in an otherwise closed container, such as a packaging container.
Various one way valves for product packaging containers have been suggested by the prior art. Such valves are useful, and may even be required, to relieve pressure build-up in a packaging container, which build-up can occur during product storage, transportation and processing, for example, during cooking and the like. Also, such valves are advantageous in situations where it is desirable to maintain a limited degree of partial vacuum in a container for a short period of time. It should be noted that valves of the type discussed herein must be produced inexpensively in order to be competitive and commercially viable.
The prior art valves have suffered from one or more problems or disadvantages. For example, many of these valves include internal moving parts which make the valves difficult and/or expensive to manufacture and add an undesirable degree of complexity which tends to make the valves unreliable in operation, particularly in repeated or long term operation. Other previous valves have involved a very tortuous gas path though the valve. This also tends to make the valve unreliable in operation.
It would be advantageous to provide a one way valve for packaging containers which solves one or more of the problems apparent in the previous valves.